不平衡电压下虚拟同步发电机功率控制策略

通过对电网电压不平衡下虚拟同步发电机输出功率的分析,提出了基于静止坐标系的功率控制策略,在不需要锁相环的情况下,利用负序电压控制分别对有功、无功功率振荡或三相电流不平衡进行抑制,既保证了虚拟同步发电机电压控制的电压源性质和惯性特性,又能够使分布式电源根据不同需求输出恒定的有功、无功功率或三相平衡电流。利用PSCAD/EMTDC软件仿真及基于RTDS的实时数字物理闭环实验,验证了所提控制策略的有效性,并对各控制策略的特性进行了量化分析。

Power control of virtual synchronous generator under unbalanced grid voltage

The output power of virtual synchronous generator under unbalanced grid voltage is analyzed and a power control strategy based on the stationary frame is proposed, which, without the phase locked loop, applies the negative-sequence voltage control to suppress the active-power oscillation, reactive-power oscillation and unbalanced three-phase currents respectively for ensuring the voltage-source nature and inertia property of the virtual synchronous generators and for enabling the distributed generation to output constant active-power, constant reactive-power or balanced three-phase currents as required. The effectiveness of the proposed control strategy is verified by PSCAD/EMTDC simulations and RTDS-based real-time digital-physical closed-loop experiments, and the features of its different control modes are quantitatively analyzed.